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B. .l. GRIGSBY. LAMP CLAMPING ATTACHMENT FOR LAMP'SOCKETS. APPLICATION FILED JAN. 8. 1917.

1,316,71 1'. PatentedSept. 23,1919.

IBERTRAM J'. GRIGSBY, 0F PEORIA, ILLINOIS, ASSIGINOR TO BENJAMIN ELECTRIC I -MA.'NUFAGTURING COMPANY, OF CHICAGO, ILLINOIS, A. CORPORATION OF ILLINOIS.

LAMP-GLAMPING ATTACHMENT FOR LAMP-SOCKETS.

Specification of Letters Patent. Patented Sept, 23, 11.919.

Application filed January 8, 1917. Serial No. 141,269.

clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

This invention pertains'to a lamp retaining device and more particularly to a device for retaining an; electric lamp in a lamp socket or. lamp receptacle.

When a lamp of the Edison or screw type is used in locations subject to intermittent or continuous vibration it tends to loosen or unscrew in its socket to the extent that there is either a poor contact between the center contact of the lamp and the socket or receptacle, or there is no contact what- 7 ever, no current flowing, or there is a destructive arcing and fusingjof the contact surfaces.

Various means have been devised and utilized with a viewof overcoming this fault. Among them there is that of employing a sharp pointed screw extending through the side of the screw-shell of the socket or re-.

ceptacle to engage the lamp base, this form rendering it difficult to remove the lamp.

Another method is to employ a curved or inwardly projecting flat spring of steel having sharp projections to bite into the lamp base.

- There are still other methods including one in which there is let through the wall of the socket a wire spring in either of two forms, a U or a Z, a portion of the spring projecting inwardly through openings in the shell of the socket. This has the disadvantage of requiring that the spring be attached to some part of the base of the socket or the walls of the same sur rounding the shell-as a support for it and in other forms several separate parts arerequired for holding the lamp which forms are expensive and likely to give trouble in use, in additionlto which they are not ap plicable to sockets now in general use but are limited to'special sockets.

The principal object of my invention is to section.

furnish an electric lamp retaining means of a most simple and inexpensive form not required to be attached to any of the parts of the lamp socket but that will hold the lamp positively so that it cannot become loosened in the socket, though permitting its easy removal.

Another object: of great importance is that of providing a lamp gripping device that can be used on known types of lamp sockets in general use either with or without an inclosure for the shell that receives the lamp.

Another object is to produce an attachment for a lamp socket for. gripping a lamp, the same being readily attached or detached and requiring no means on said socket to fasten it in place. A

Another object is to furnish'a lamp retaining device of a single part for a lamp socket for gripping the threaded part of the lamp base and that can be adapted for and be used with any type or form ofsocket and which in one of its forms can be used in narrow or constricted spaces within said socket.

To the end that my invention may be readily understood, I have provided the ac comp-anying drawing, in which:

Figure 1 is an elevation of an electric lamp socket showing my invention in connection therewith.

Fig; 2 shows the same in section as viewed endwise.

Fig. 3 is an elevation of the socket as viewed in the direction of the dart in Fig. 2, showing part of my invention in cross Fig. 4 is a vertical section of'a slightly difierent form of socket and a modified form of the part entering into my improved structure.

Fig. 5 shows, in perspectivaone of the portions shown in Fig. 4; and,

Fig. 6 also shows, in-perspective, a modification of the-same. Y

A represents an electric lamp socket, whose screw-contact shell B has two slots C, one being substantially diametrically opposite the other, Figs. 2 and 3, each said slot being preferably at the bottom of one of the inwardly formed threads.

l) represents a closed or normally closed loop of spring wire'preferably elongated, or

the best resiliency of the wire when pressure is applied in screwing in the lamp as well as holding power or friction to hold the lamp, but which in any event is not less than the outside diameter of thethreads of said screw-contact shell.

When I speak of a normally closed loop I mean a loop constructed of a single length of .wire whose ends may substantially abut and which will be normally closed but which may spring apart when the lamp is screwed into place. The abutting ends may be fused together, or otherwise fastened, of course,

but from a manufacturing standpoint securing the ends together is not desirable. A gage ,of spring-wire that will provide sufficient rigidity is all that is required.

The loop is ut in position by springing it over the she 1, its longest sides or extensions being allowed to enter the slots, the

latter being of a width greater in extent than the diameter of the wire and permitting the spring to freely move or flex as the lamp is inserted or withdrawn and to conform to the threads of the latter.

When there is no surrounding part for the screw-contact shell and where it does not matter how long the spring loop may be, it may appear as in Figs. 1 and 2 but when used with some such structure as is illustrated in Fig. 4, for example, wherein the shell may be inclosed by an outer casing and adapted to receive the loop the length of the latter may be reduced without losing the proper or desired resiliency by bending its ends so that they lie at an angle to the plane of said loop as clearly shown at E in Figs.

4 and 5 or as in Fig. 6. This permits thespring to be confined within narrow limits with respect to its length.

As the lamp, not shown, is secured into the socket its base which is usually of a slightly rounded or conical form at its end will engage the loop and spring its sides outwardly, said sides engaging in the bottom of the threads of the lamp base providing a very firm grip so that when the end terminal of said lamp has contact with the terminal at the bottom of the socket no amount of jar or vibration will cause the lamp to work loose or the contact points to become separated. In other words, the spring in extending through the slots reacts on the lamp base with a firm pressure with the result stated.

When the spring is forced outward in the manner described it is held'in position not only by the thickness of the metal wall of the screw-contact shell but in practice it will be found that the height of the thread on the lamp base is somewhat less than the depth of the thread rolled on the said screwcontact shell and, therefore, the spring cannot be forced out of the slots beyond the greatest diameter of the threads of said shell.

My construction furnishes an exceedingly simple and effective arrangement not dependent upon any means whatsoever for supporting the spring other than that provided by the edges of the shell within the slots.

The form shown in Figs. 4 and 6 is but one of the ways in which the spring may be constructed in order that it may be used in confined places, 1t being understood that other forms may be adopted as well.

My peculiar type of clamping attachment differs from others of which I am aware in v that it is but a' single part and its form admits of its being readily applied to the common forms of lamp sockets in general use. Where an inclosing part for the shell is used the loop can be employed in any of the forms shown, whereas in other types of clamping devices specially formed sockets are required to ald in holding the parts in operative position.

'Due to the structure provided lamps that v are located in places where they are subected to vibrations that would cause them to loosen are securely held by the employment of the loop'in the form of an elongated ring and is possible to obtain a more positive pressure on the lamp base than by the use of other forms of which I am aware.

In .some of the late types of lamp sockets the base has secured thereto the threaded shell B as in Fig. 1 with no surrounding porcelain structure and any gripping device used for the lamp is supported from the base by means of extended parts held in said base, whereas in my structure no such extended, parts are necessary, the loop being wholly independent of the fastening means.-

I-Iaving thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In combination, a threaded screw-consocket adapted to engage the threaded base of a lamp, opposite portions of the spring being bent at an angle to the plane of the main portion.

3. In combination, a threaded screw-contact shell, for receiving a lamp, havin oppositely disposed slots piercing it, a c osed sprin taking the form of a ring having two 1lferent measurements in planes lying substantially at right angles to one another, said spring in its narrowest measurement engaging in the slots and lying inside the shell to engage the base of a lamp screwed therein, the extremities of the ring in its longest measurement lying outside the shell, one of said extremities being bent substantially perpendicularly to the plane of the rm f In combination, threaded screw-contact shell for receiving a lamp, having oppositely disposed slots piercing it, a c osed sprin taking the form of a ring having two lfi'erent measurements in planes lying substantially at right angles to one another, said spring in its narrowest measurement engaging in the slots and lying inside the shell to engage the base of a lampserewed therein, the extremities of the ring in its longest measurement lying outside the shell, and said extremities being bent substantially perpendicularly to the plane of the ring.

In testimony whereof I afiix my signature in presence of two witnesses.

BERTRAM J. GRIGSBY.

Witnesses:

L. M. THURLOW, L. O. EAGLETON. 

